/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file yapf_node.hpp Node in the pathfinder's graph. */

#ifndef YAPF_NODE_HPP
#define YAPF_NODE_HPP

/** Yapf Node Key that evaluates hash from (and compares) tile & exit dir. */
struct CYapfNodeKeyExitDir {
	TileIndex      m_tile;
	Trackdir       m_td;
	DiagDirection  m_exitdir;

	inline void Set(TileIndex tile, Trackdir td)
	{
		m_tile = tile;
		m_td = td;
		m_exitdir = (m_td == INVALID_TRACKDIR) ? INVALID_DIAGDIR : TrackdirToExitdir(m_td);
	}

	inline int CalcHash() const {return m_exitdir | (m_tile << 2);}
	inline bool operator == (const CYapfNodeKeyExitDir& other) const {return (m_tile == other.m_tile) && (m_exitdir == other.m_exitdir);}

	void Dump(DumpTarget &dmp) const
	{
		dmp.WriteTile("m_tile", m_tile);
		dmp.WriteEnumT("m_td", m_td);
		dmp.WriteEnumT("m_exitdir", m_exitdir);
	}
};

struct CYapfNodeKeyTrackDir : public CYapfNodeKeyExitDir
{
	inline int CalcHash() const {return m_td | (m_tile << 4);}
	inline bool operator == (const CYapfNodeKeyTrackDir& other) const {return (m_tile == other.m_tile) && (m_td == other.m_td);}
};

/** Yapf Node base */
template <class Tkey_, class Tnode>
struct CYapfNodeT {
	typedef Tkey_ Key;
	typedef Tnode Node;

	Tkey_       m_key;
	Node       *m_hash_next;
	Node       *m_parent;
	int         m_cost;
	int         m_estimate;

	inline void Set(Node *parent, TileIndex tile, Trackdir td, bool is_choice)
	{
		m_key.Set(tile, td);
		m_hash_next = NULL;
		m_parent = parent;
		m_cost = 0;
		m_estimate = 0;
	}

	inline Node *GetHashNext() {return m_hash_next;}
	inline void SetHashNext(Node *pNext) {m_hash_next = pNext;}
	inline TileIndex GetTile() const {return m_key.m_tile;}
	inline Trackdir GetTrackdir() const {return m_key.m_td;}
	inline const Tkey_& GetKey() const {return m_key;}
	inline int GetCost() const {return m_cost;}
	inline int GetCostEstimate() const {return m_estimate;}
	inline bool operator < (const Node& other) const {return m_estimate < other.m_estimate;}

	void Dump(DumpTarget &dmp) const
	{
		dmp.WriteStructT("m_key", &m_key);
		dmp.WriteStructT("m_parent", m_parent);
		dmp.WriteLine("m_cost = %d", m_cost);
		dmp.WriteLine("m_estimate = %d", m_estimate);
	}
};

#endif /* YAPF_NODE_HPP */